1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
|
/*
* Save/restore floating point context for signal handlers.
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 1999, 2000 Kaz Kojima & Niibe Yutaka
* Copyright (C) 2006 ST Microelectronics Ltd. (denorm support)
*
* FIXME! These routines have not been tested for big endian case.
*/
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/io.h>
#include <cpu/fpu.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/fpu.h>
/* The PR (precision) bit in the FP Status Register must be clear when
* an frchg instruction is executed, otherwise the instruction is undefined.
* Executing frchg with PR set causes a trap on some SH4 implementations.
*/
#define FPSCR_RCHG 0x00000000
extern unsigned long long float64_div(unsigned long long a,
unsigned long long b);
extern unsigned long int float32_div(unsigned long int a, unsigned long int b);
extern unsigned long long float64_mul(unsigned long long a,
unsigned long long b);
extern unsigned long int float32_mul(unsigned long int a, unsigned long int b);
extern unsigned long long float64_add(unsigned long long a,
unsigned long long b);
extern unsigned long int float32_add(unsigned long int a, unsigned long int b);
extern unsigned long long float64_sub(unsigned long long a,
unsigned long long b);
extern unsigned long int float32_sub(unsigned long int a, unsigned long int b);
static unsigned int fpu_exception_flags;
/*
* Save FPU registers onto task structure.
* Assume called with FPU enabled (SR.FD=0).
*/
void save_fpu(struct task_struct *tsk, struct pt_regs *regs)
{
unsigned long dummy;
clear_tsk_thread_flag(tsk, TIF_USEDFPU);
enable_fpu();
asm volatile ("sts.l fpul, @-%0\n\t"
"sts.l fpscr, @-%0\n\t"
"lds %2, fpscr\n\t"
"frchg\n\t"
"fmov.s fr15, @-%0\n\t"
"fmov.s fr14, @-%0\n\t"
"fmov.s fr13, @-%0\n\t"
"fmov.s fr12, @-%0\n\t"
"fmov.s fr11, @-%0\n\t"
"fmov.s fr10, @-%0\n\t"
"fmov.s fr9, @-%0\n\t"
"fmov.s fr8, @-%0\n\t"
"fmov.s fr7, @-%0\n\t"
"fmov.s fr6, @-%0\n\t"
"fmov.s fr5, @-%0\n\t"
"fmov.s fr4, @-%0\n\t"
"fmov.s fr3, @-%0\n\t"
"fmov.s fr2, @-%0\n\t"
"fmov.s fr1, @-%0\n\t"
"fmov.s fr0, @-%0\n\t"
"frchg\n\t"
"fmov.s fr15, @-%0\n\t"
"fmov.s fr14, @-%0\n\t"
"fmov.s fr13, @-%0\n\t"
"fmov.s fr12, @-%0\n\t"
"fmov.s fr11, @-%0\n\t"
"fmov.s fr10, @-%0\n\t"
"fmov.s fr9, @-%0\n\t"
"fmov.s fr8, @-%0\n\t"
"fmov.s fr7, @-%0\n\t"
"fmov.s fr6, @-%0\n\t"
"fmov.s fr5, @-%0\n\t"
"fmov.s fr4, @-%0\n\t"
"fmov.s fr3, @-%0\n\t"
"fmov.s fr2, @-%0\n\t"
"fmov.s fr1, @-%0\n\t"
"fmov.s fr0, @-%0\n\t"
"lds %3, fpscr\n\t":"=r" (dummy)
:"0"((char *)(&tsk->thread.fpu.hard.status)),
"r"(FPSCR_RCHG), "r"(FPSCR_INIT)
:"memory");
disable_fpu();
release_fpu(regs);
}
static void restore_fpu(struct task_struct *tsk)
{
unsigned long dummy;
enable_fpu();
asm volatile ("lds %2, fpscr\n\t"
"fmov.s @%0+, fr0\n\t"
"fmov.s @%0+, fr1\n\t"
"fmov.s @%0+, fr2\n\t"
"fmov.s @%0+, fr3\n\t"
"fmov.s @%0+, fr4\n\t"
"fmov.s @%0+, fr5\n\t"
"fmov.s @%0+, fr6\n\t"
"fmov.s @%0+, fr7\n\t"
"fmov.s @%0+, fr8\n\t"
"fmov.s @%0+, fr9\n\t"
"fmov.s @%0+, fr10\n\t"
"fmov.s @%0+, fr11\n\t"
"fmov.s @%0+, fr12\n\t"
"fmov.s @%0+, fr13\n\t"
"fmov.s @%0+, fr14\n\t"
"fmov.s @%0+, fr15\n\t"
"frchg\n\t"
"fmov.s @%0+, fr0\n\t"
"fmov.s @%0+, fr1\n\t"
"fmov.s @%0+, fr2\n\t"
"fmov.s @%0+, fr3\n\t"
"fmov.s @%0+, fr4\n\t"
"fmov.s @%0+, fr5\n\t"
"fmov.s @%0+, fr6\n\t"
"fmov.s @%0+, fr7\n\t"
"fmov.s @%0+, fr8\n\t"
"fmov.s @%0+, fr9\n\t"
"fmov.s @%0+, fr10\n\t"
"fmov.s @%0+, fr11\n\t"
"fmov.s @%0+, fr12\n\t"
"fmov.s @%0+, fr13\n\t"
"fmov.s @%0+, fr14\n\t"
"fmov.s @%0+, fr15\n\t"
"frchg\n\t"
"lds.l @%0+, fpscr\n\t"
"lds.l @%0+, fpul\n\t"
:"=r" (dummy)
:"0"(&tsk->thread.fpu), "r"(FPSCR_RCHG)
:"memory");
disable_fpu();
}
/*
* Load the FPU with signalling NANS. This bit pattern we're using
* has the property that no matter wether considered as single or as
* double precision represents signaling NANS.
*/
static void fpu_init(void)
{
enable_fpu();
asm volatile ( "lds %0, fpul\n\t"
"lds %1, fpscr\n\t"
"fsts fpul, fr0\n\t"
"fsts fpul, fr1\n\t"
"fsts fpul, fr2\n\t"
"fsts fpul, fr3\n\t"
"fsts fpul, fr4\n\t"
"fsts fpul, fr5\n\t"
"fsts fpul, fr6\n\t"
"fsts fpul, fr7\n\t"
"fsts fpul, fr8\n\t"
"fsts fpul, fr9\n\t"
"fsts fpul, fr10\n\t"
"fsts fpul, fr11\n\t"
"fsts fpul, fr12\n\t"
"fsts fpul, fr13\n\t"
"fsts fpul, fr14\n\t"
"fsts fpul, fr15\n\t"
"frchg\n\t"
"fsts fpul, fr0\n\t"
"fsts fpul, fr1\n\t"
"fsts fpul, fr2\n\t"
"fsts fpul, fr3\n\t"
"fsts fpul, fr4\n\t"
"fsts fpul, fr5\n\t"
"fsts fpul, fr6\n\t"
"fsts fpul, fr7\n\t"
"fsts fpul, fr8\n\t"
"fsts fpul, fr9\n\t"
"fsts fpul, fr10\n\t"
"fsts fpul, fr11\n\t"
"fsts fpul, fr12\n\t"
"fsts fpul, fr13\n\t"
"fsts fpul, fr14\n\t"
"fsts fpul, fr15\n\t"
"frchg\n\t"
"lds %2, fpscr\n\t"
: /* no output */
:"r" (0), "r"(FPSCR_RCHG), "r"(FPSCR_INIT));
disable_fpu();
}
/**
* denormal_to_double - Given denormalized float number,
* store double float
*
* @fpu: Pointer to sh_fpu_hard structure
* @n: Index to FP register
*/
static void denormal_to_double(struct sh_fpu_hard_struct *fpu, int n)
{
unsigned long du, dl;
unsigned long x = fpu->fpul;
int exp = 1023 - 126;
if (x != 0 && (x & 0x7f800000) == 0) {
du = (x & 0x80000000);
while ((x & 0x00800000) == 0) {
x <<= 1;
exp--;
}
x &= 0x007fffff;
du |= (exp << 20) | (x >> 3);
dl = x << 29;
fpu->fp_regs[n] = du;
fpu->fp_regs[n + 1] = dl;
}
}
/**
* ieee_fpe_handler - Handle denormalized number exception
*
* @regs: Pointer to register structure
*
* Returns 1 when it's handled (should not cause exception).
*/
static int ieee_fpe_handler(struct pt_regs *regs)
{
unsigned short insn = *(unsigned short *)regs->pc;
unsigned short finsn;
unsigned long nextpc;
int nib[4] = {
(insn >> 12) & 0xf,
(insn >> 8) & 0xf,
(insn >> 4) & 0xf,
insn & 0xf
};
if (nib[0] == 0xb || (nib[0] == 0x4 && nib[2] == 0x0 && nib[3] == 0xb))
regs->pr = regs->pc + 4; /* bsr & jsr */
if (nib[0] == 0xa || nib[0] == 0xb) {
/* bra & bsr */
nextpc = regs->pc + 4 + ((short)((insn & 0xfff) << 4) >> 3);
finsn = *(unsigned short *)(regs->pc + 2);
} else if (nib[0] == 0x8 && nib[1] == 0xd) {
/* bt/s */
if (regs->sr & 1)
nextpc = regs->pc + 4 + ((char)(insn & 0xff) << 1);
else
nextpc = regs->pc + 4;
finsn = *(unsigned short *)(regs->pc + 2);
} else if (nib[0] == 0x8 && nib[1] == 0xf) {
/* bf/s */
if (regs->sr & 1)
nextpc = regs->pc + 4;
else
nextpc = regs->pc + 4 + ((char)(insn & 0xff) << 1);
finsn = *(unsigned short *)(regs->pc + 2);
} else if (nib[0] == 0x4 && nib[3] == 0xb &&
(nib[2] == 0x0 || nib[2] == 0x2)) {
/* jmp & jsr */
nextpc = regs->regs[nib[1]];
finsn = *(unsigned short *)(regs->pc + 2);
} else if (nib[0] == 0x0 && nib[3] == 0x3 &&
(nib[2] == 0x0 || nib[2] == 0x2)) {
/* braf & bsrf */
nextpc = regs->pc + 4 + regs->regs[nib[1]];
finsn = *(unsigned short *)(regs->pc + 2);
} else if (insn == 0x000b) {
/* rts */
nextpc = regs->pr;
finsn = *(unsigned short *)(regs->pc + 2);
} else {
nextpc = regs->pc + instruction_size(insn);
finsn = insn;
}
if ((finsn & 0xf1ff) == 0xf0ad) {
/* fcnvsd */
struct task_struct *tsk = current;
save_fpu(tsk, regs);
if ((tsk->thread.fpu.hard.fpscr & FPSCR_CAUSE_ERROR))
/* FPU error */
denormal_to_double(&tsk->thread.fpu.hard,
(finsn >> 8) & 0xf);
else
return 0;
regs->pc = nextpc;
return 1;
} else if ((finsn & 0xf00f) == 0xf002) {
/* fmul */
struct task_struct *tsk = current;
int fpscr;
int n, m, prec;
unsigned int hx, hy;
n = (finsn >> 8) & 0xf;
m = (finsn >> 4) & 0xf;
hx = tsk->thread.fpu.hard.fp_regs[n];
hy = tsk->thread.fpu.hard.fp_regs[m];
fpscr = tsk->thread.fpu.hard.fpscr;
prec = fpscr & FPSCR_DBL_PRECISION;
if ((fpscr & FPSCR_CAUSE_ERROR)
&& (prec && ((hx & 0x7fffffff) < 0x00100000
|| (hy & 0x7fffffff) < 0x00100000))) {
long long llx, lly;
/* FPU error because of denormal (doubles) */
llx = ((long long)hx << 32)
| tsk->thread.fpu.hard.fp_regs[n + 1];
lly = ((long long)hy << 32)
| tsk->thread.fpu.hard.fp_regs[m + 1];
llx = float64_mul(llx, lly);
tsk->thread.fpu.hard.fp_regs[n] = llx >> 32;
tsk->thread.fpu.hard.fp_regs[n + 1] = llx & 0xffffffff;
} else if ((fpscr & FPSCR_CAUSE_ERROR)
&& (!prec && ((hx & 0x7fffffff) < 0x00800000
|| (hy & 0x7fffffff) < 0x00800000))) {
/* FPU error because of denormal (floats) */
hx = float32_mul(hx, hy);
tsk->thread.fpu.hard.fp_regs[n] = hx;
} else
return 0;
regs->pc = nextpc;
return 1;
} else if ((finsn & 0xf00e) == 0xf000) {
/* fadd, fsub */
struct task_struct *tsk = current;
int fpscr;
int n, m, prec;
unsigned int hx, hy;
n = (finsn >> 8) & 0xf;
m = (finsn >> 4) & 0xf;
hx = tsk->thread.fpu.hard.fp_regs[n];
hy = tsk->thread.fpu.hard.fp_regs[m];
fpscr = tsk->thread.fpu.hard.fpscr;
prec = fpscr & FPSCR_DBL_PRECISION;
if ((fpscr & FPSCR_CAUSE_ERROR)
&& (prec && ((hx & 0x7fffffff) < 0x00100000
|| (hy & 0x7fffffff) < 0x00100000))) {
long long llx, lly;
/* FPU error because of denormal (doubles) */
llx = ((long long)hx << 32)
| tsk->thread.fpu.hard.fp_regs[n + 1];
lly = ((long long)hy << 32)
| tsk->thread.fpu.hard.fp_regs[m + 1];
if ((finsn & 0xf00f) == 0xf000)
llx = float64_add(llx, lly);
else
llx = float64_sub(llx, lly);
tsk->thread.fpu.hard.fp_regs[n] = llx >> 32;
tsk->thread.fpu.hard.fp_regs[n + 1] = llx & 0xffffffff;
} else if ((fpscr & FPSCR_CAUSE_ERROR)
&& (!prec && ((hx & 0x7fffffff) < 0x00800000
|| (hy & 0x7fffffff) < 0x00800000))) {
/* FPU error because of denormal (floats) */
if ((finsn & 0xf00f) == 0xf000)
hx = float32_add(hx, hy);
else
hx = float32_sub(hx, hy);
tsk->thread.fpu.hard.fp_regs[n] = hx;
} else
return 0;
regs->pc = nextpc;
return 1;
} else if ((finsn & 0xf003) == 0xf003) {
/* fdiv */
struct task_struct *tsk = current;
int fpscr;
int n, m, prec;
unsigned int hx, hy;
n = (finsn >> 8) & 0xf;
m = (finsn >> 4) & 0xf;
hx = tsk->thread.fpu.hard.fp_regs[n];
hy = tsk->thread.fpu.hard.fp_regs[m];
fpscr = tsk->thread.fpu.hard.fpscr;
prec = fpscr & FPSCR_DBL_PRECISION;
if ((fpscr & FPSCR_CAUSE_ERROR)
&& (prec && ((hx & 0x7fffffff) < 0x00100000
|| (hy & 0x7fffffff) < 0x00100000))) {
long long llx, lly;
/* FPU error because of denormal (doubles) */
llx = ((long long)hx << 32)
| tsk->thread.fpu.hard.fp_regs[n + 1];
lly = ((long long)hy << 32)
| tsk->thread.fpu.hard.fp_regs[m + 1];
llx = float64_div(llx, lly);
tsk->thread.fpu.hard.fp_regs[n] = llx >> 32;
tsk->thread.fpu.hard.fp_regs[n + 1] = llx & 0xffffffff;
} else if ((fpscr & FPSCR_CAUSE_ERROR)
&& (!prec && ((hx & 0x7fffffff) < 0x00800000
|| (hy & 0x7fffffff) < 0x00800000))) {
/* FPU error because of denormal (floats) */
hx = float32_div(hx, hy);
tsk->thread.fpu.hard.fp_regs[n] = hx;
} else
return 0;
regs->pc = nextpc;
return 1;
}
return 0;
}
void float_raise(unsigned int flags)
{
fpu_exception_flags |= flags;
}
int float_rounding_mode(void)
{
struct task_struct *tsk = current;
int roundingMode = FPSCR_ROUNDING_MODE(tsk->thread.fpu.hard.fpscr);
return roundingMode;
}
BUILD_TRAP_HANDLER(fpu_error)
{
struct task_struct *tsk = current;
TRAP_HANDLER_DECL;
save_fpu(tsk, regs);
fpu_exception_flags = 0;
if (ieee_fpe_handler(regs)) {
tsk->thread.fpu.hard.fpscr &=
~(FPSCR_CAUSE_MASK | FPSCR_FLAG_MASK);
tsk->thread.fpu.hard.fpscr |= fpu_exception_flags;
/* Set the FPSCR flag as well as cause bits - simply
* replicate the cause */
tsk->thread.fpu.hard.fpscr |= (fpu_exception_flags >> 10);
grab_fpu(regs);
restore_fpu(tsk);
set_tsk_thread_flag(tsk, TIF_USEDFPU);
if ((((tsk->thread.fpu.hard.fpscr & FPSCR_ENABLE_MASK) >> 7) &
(fpu_exception_flags >> 2)) == 0) {
return;
}
}
force_sig(SIGFPE, tsk);
}
BUILD_TRAP_HANDLER(fpu_state_restore)
{
struct task_struct *tsk = current;
TRAP_HANDLER_DECL;
grab_fpu(regs);
if (!user_mode(regs)) {
printk(KERN_ERR "BUG: FPU is used in kernel mode.\n");
return;
}
if (used_math()) {
/* Using the FPU again. */
restore_fpu(tsk);
} else {
/* First time FPU user. */
fpu_init();
set_used_math();
}
set_tsk_thread_flag(tsk, TIF_USEDFPU);
}
|
